For the focaccia:
In a large mixing bowl, whisk together flour and salt. In A separate small bowl, whisk together the warm water, yeast, and sugar. After a few minutes, a foamy top should emerge in the liquid, letting you know that the yeast is alive. Make a hole in the flour and slowly incorporate the water into the flour by mixing just the water with a spoon, until it grabs all the flour. When it becomes difficult to mix with the spoon, bring it together with your hands until it’s at an even consistency, no kneading required. Move it to the refrigerator overnight. When ready to bake, turn the dough out into a 30x 40 cm baking sheet greased with 60 ml of olive oil. Allow it to rise between 20 minutes to an hour and use your fingers to press down to the sheet all over – this prevents a big bubble somewhere in the dough. It should look polka-dotted with little holes.
For the topping:
Chop the NURI Sardines and spread them over the dough, with a healthy drizzle of NURI Olive oil and a sprinkle of sea salt, and bake at 230 degrees for about 15 minutes, rotating once until golden brown all over. After a couple of minutes (not steaming out), top the focaccia with the arugula and parmesan flakes and serve warm.